Density Measurement Problems - Emerson Micro Motion LNG Series Configuration And Use Manual

10.4

Density measurement problems

Table 10-3: Density measurement problems and recommended actions
Problem Possible causes
Inaccurate density •
reading •
•
•
•
•
•
•
•
Unusually high densi- •
ty reading •
•
•
•
•
Unusually low density •
reading •
•
Configuration and Use Manual
Problem with process fluid
Incorrect density calibration factors
Wiring problem
Incorrect grounding
Two-phase flow
Plugged or coated sensor tube
Incorrect sensor orientation
RTD failure
Physical characteristics of sensor have
changed
Plugged or coated sensor tube
Incorrect density calibration factors
Incorrect temperature measurement
RTD problem
In high-frequency meters, this can indicate
erosion or corrosion
In low-frequency meters, this can indicate
tube fouling
Two-phase flow
Ensure that all of the calibration parame-
ters have been entered correctly. See the
sensor tag or the calibration sheet for your
meter.
In low-frequency meters, this can indicate
erosion or corrosion
Recommended actions
• Check your process conditions against the
values reported by the device.
• Ensure that all of the calibration parame-
ters have been entered correctly. See the
sensor tag or the calibration sheet for your
meter.
• Check the wiring between the sensor and
the transmitter.
• Check the grounding of all components.
• Verify all of the characterization or calibra-
tion parameters. See the sensor tag or the
calibration sheet for your meter.
• Check for two-phase flow.
• If two sensors with similar frequency are
too near each other, separate them.
• Purge the sensor tubes.
• Ensure that all of the calibration parame-
ters have been entered correctly. See the
sensor tag or the calibration sheet for your
meter.
• Verify all of the characterization or calibra-
tion parameters. See the sensor tag or the
calibration sheet for your meter.
• Purge the sensor tubes.
• Check for coating in the flow tubes.
• Check your process conditions against the
values reported by the device.
• Check for two-phase flow.
• Verify all of the characterization or calibra-
tion parameters. See the sensor tag or the
calibration sheet for your meter.
• Check the wiring between the sensor and
the transmitter.
• Check for tube erosion, especially if the
process fluid is abrasive.
Troubleshooting
77